Buggy code:
public class FieldMetaData extends Extensions implements Commentable , MetaDataContext , MetaDataModes , ValueMetaData { public static final int NULL_UNSET = - 1 ; public static final int NULL_NONE = 0 ; public static final int NULL_DEFAULT = 1 ; public static final int NULL_EXCEPTION = 2 ; public static final int MANAGE_PERSISTENT = 3 ; public static final int MANAGE_TRANSACTIONAL = 1 ; public static final int MANAGE_NONE = 0 ; private static final Localizer _loc = Localizer . forPackage ( FieldMetaData . class ) ; private static final int DFG_FALSE = 1 ; private static final int DFG_TRUE = 2 ; private static final int DFG_EXPLICIT = 4 ; private static final Method DEFAULT_METHOD ; private final ValueMetaData _val ; private final ValueMetaData _key ; private final ValueMetaData _elem ; private final ClassMetaData _owner ; private final String _name ; private Class _dec = null ; private ClassMetaData _decMeta = null ; private String _fullName = null ; private String _embedFullName = null ; private int _resMode = MODE_NONE ; private String [ ] _comments = null ; private int _listIndex = - 1 ; private Class _proxyClass = null ; private Object _initializer = null ; private boolean _transient = false ; private boolean _primKey = false ; private Boolean _version = null ; private int _nullValue = FieldMetaData . NULL_UNSET ; private int _manage = FieldMetaData . MANAGE_PERSISTENT ; private int _index = - 1 ; private int _decIndex = - 1 ; private int _pkIndex = - 1 ; private boolean _explicit = false ; private int _dfg = 0 ; private Set _fgSet = null ; private String [ ] _fgs = null ; private String _lfg = null ; private Boolean _lrs = null ; private String _extName = null ; private String _factName = null ; private String _extString = null ; private Map _extValues = Collections . EMPTY_MAP ; private Map _fieldValues = Collections . EMPTY_MAP ; private transient FieldMetaData . MemberProvider _backingMember = null ; private transient Method _extMethod = FieldMetaData . DEFAULT_METHOD ; private transient Member _factMethod = FieldMetaData . DEFAULT_METHOD ; private boolean _intermediate = true ; private Boolean _implData = Boolean . TRUE ; private int _valStrategy = - 1 ; private int _upStrategy = - 1 ; private String _seqName = ClassMetaData . DEFAULT_STRING ; private SequenceMetaData _seqMeta = null ; private String _mappedBy = null ; private FieldMetaData _mappedByMeta = null ; private FieldMetaData [ ] _inverses = null ; private String _inverse = ClassMetaData . DEFAULT_STRING ; private Order [ ] _orders = null ; private String _orderDec = null ; protected FieldMetaData ( String name , Class type , ClassMetaData owner ) { } public void backingMember ( Member member ) { } public Member getBackingMember ( ) { <START_BUG> return _backingMember . getMember ( ) ; <END_BUG> } public MetaDataRepository getRepository ( ) { } public ClassMetaData getDefiningMetaData ( ) { } public Class getDeclaringType ( ) { } public void setDeclaringType ( Class cls ) { } public ClassMetaData getDeclaringMetaData ( ) { } public String getName ( ) { } public String getFullName ( ) { } public String getFullName ( boolean embedOwner ) { } public ValueMetaData getValue ( ) { } public ValueMetaData getKey ( ) { } public ValueMetaData getElement ( ) { } public boolean isMapped ( ) { } public Class getProxyType ( ) { } public void setProxyType ( Class type ) { } public Object getInitializer ( ) { } public void setInitializer ( Object initializer ) { } public boolean isTransient ( ) { } public void setTransient ( boolean trans ) { } public int getIndex ( ) { } public void setIndex ( int index ) { } public int getDeclaredIndex ( ) { } public void setDeclaredIndex ( int index ) { } public int getListingIndex ( ) { } public void setListingIndex ( int index ) { } public int getPrimaryKeyIndex ( ) { } public void setPrimaryKeyIndex ( int index ) { } public int getManagement ( ) { } public void setManagement ( int manage ) { } public boolean isPrimaryKey ( ) { } public void setPrimaryKey ( boolean primKey ) { } public int getObjectIdFieldTypeCode ( ) { } public Class getObjectIdFieldType ( ) { } public boolean isVersion ( ) { } public void setVersion ( boolean version ) { } public boolean isInDefaultFetchGroup ( ) { } public void setInDefaultFetchGroup ( boolean dfg ) { } public boolean isDefaultFetchGroupExplicit ( ) { } public void setDefaultFetchGroupExplicit ( boolean explicit ) { } public String [ ] getCustomFetchGroups ( ) { } public String getLoadFetchGroup ( ) { } public void setLoadFetchGroup ( String lfg ) { } public boolean isInFetchGroup ( String fg ) { } public void setInFetchGroup ( String fg , boolean in ) { } public int getNullValue ( ) { } public void setNullValue ( int nullValue ) { } public boolean isExplicit ( ) { } public void setExplicit ( boolean explicit ) { } public String getMappedBy ( ) { } public void setMappedBy ( String mapped ) { } public FieldMetaData getMappedByMetaData ( ) { } public String getInverse ( ) { } public void setInverse ( String inverse ) { } public FieldMetaData [ ] getInverseMetaDatas ( ) { } public int getValueStrategy ( ) { } public void setValueStrategy ( int strategy ) { } public String getValueSequenceName ( ) { } public void setValueSequenceName ( String seqName ) { } public SequenceMetaData getValueSequenceMetaData ( ) { } public int getUpdateStrategy ( ) { } public void setUpdateStrategy ( int strategy ) { } public boolean isLRS ( ) { } public void setLRS ( boolean lrs ) { } public boolean usesIntermediate ( ) { } public void setUsesIntermediate ( boolean intermediate ) { } public Boolean usesImplData ( ) { } public void setUsesImplData ( Boolean implData ) { }

Fix:
return ( _backingMember ) == null ? null : _backingMember . getMember ( ) ;